1. Field of the Invention
The present device relates to a temperature indicator having a gravity biased indicating pin for showing that the interior of a freezer has reached an over-temperature, or thaw, condition.
2. Description of the Prior Art
Temperature indicators are known in which gravity influences an indicating means; for instance, in U.S. Pat. No. 2,362,424 a multiple position temperature indicator includes gravity actuated semaphores to show movement of a bimetal strip having two opposed legs. In U.S. Pat. No. 1,595,734, an adjustable lever with a hook engages a bimetallic element to hold an indicator until a predetermined temperature condition is reached, at which time the bimetal moves to release the hook and enables the indicator to fall to an open position.
In U.S. Pat. No. 3,452,706, a snap action bimetal releases a latch that enables a spring to move a plunger outward to an indicating position. An indicator for sensing the depletion of toner within a copier is disclosed in U.S. Pat. No. 3,915,340 in which a magnet on a pivot arm is attracted to a magnetic carrier in the toner. When the toner is depleted, the pivot arm moves to close a switch that illuminates a light.